Parks and Wildlife Service (PWS) officer Michael Spaulding said dog owners needed to be responsible for the actions of their pets

"Investigations into all the circumstances surrounding the deaths are continuing and so we would like to encourage anyone who may have any information to contact us to assist in our investigations," he said.

"We would like to remind dog owners of the need to take responsibility for their animals at all times as dogs have the capacity to do a lot of damage to penguin colonies in a short period of time.

Dog access in reserves is restricted and penalties apply under the law, Mr Spaulding said.

He said all reports of alleged unlawful harming of wildlife would be "regarded extremely seriously by the department".

'Laws need to make dog owners think twice'

Birdlife Tasmania convenor Dr Eric Woehler said he was shocked by the deaths at the start of the penguin breeding season.

"It's a catastrophic loss to that colony — it will take years, if not decades, to recover," he said.

Dr Woehler said dog attacks were one of the most significant threats to Tasmania's little penguins, along with gillnets.

He called for the owners of the dogs involved to be identified and prosecuted, but feared the current penalties would not be sufficient.

"We need really strong laws so that anytime a dog is found to have killed penguins or other forms of wildlife in Tasmania that the dog owners think twice about letting their dogs loose at night when they have no control over them," he said.

Dr Woehler also called for fencing at the Low Head Conservation Area to be improved.

Dog owners found to be responsible for pets that kill wildlife can face fines and in some cases the dog could be destroyed.

'Install CCTV cameras at these beaches'

Tasmanian Greens leader Cassy O'Connor called for more effective monitoring of penguin colonies to prevent further deaths.

"Here we go again, where people who don't understand how precious these animals are or who don't keep their dogs in at night are responsible for the death of a precious animal that is really hanging on to its existence on our coastline," she said.

"We do need to have better monitoring of penguin nesting sites, more resources put into parks and wildlife so that they can do that.

"There needs to be, potentially, CCTV cameras put at significant nesting sites because we can't keep being in a situation where every month or two we're hearing another story about these penguins being killed."

George Town Mayor Bridget Archer said the deaths were "completely unacceptable".

"That area is off limits for dogs," she said.

"It's simply not acceptable for dogs to be in that area at all."

Councillor Archer said the council's animal control officer was already very vigilant about stray dogs and would concentrate on the conservation area in the coming days.

"There is a significant amount more work needs to be done to encourage people to be more responsible around their ownership of animals, and dogs in particular."

Anyone with information about this incident is asked to contact, DPIPWE's Wildlife Operations Branch on 0427 437 020, PWS on 1300 827 727 or Crime Stoppers on 1800 333 000.